Washington — Paul Whelan, the American businessman who the U.S. considers to be wrongfully detained by Russia, was attacked Tuesday by a fellow prisoner at the labor camp where he is serving a 16 year sentence, according to his family.

His brother David Whelan wrote in an email that Paul detailed the incident in a phone call to his parents. Paul said a fellow prisoner blocked part of a production line as he was working at a sewing table.

After Whelan repeatedly asked the prisoner to move out of the way, “the prisoner hit Paul in the face, breaking Paul’s glasses in the process, and attempted to hit him a second time,” he wrote. “Paul stood up to block the second hit and other prisoners intervened to prevent the prisoner continuing to attack Paul.” 

David Whelan said his brother described the attack as “relatively minor” and reported it to a prison official. 

Paul Whelan is “concerned that these sorts of attacks can occur any time and, due to the various sharp implements in the workshop including the shears the other prisoner was holding today, could escalate into a far more serious attack,” David Whelan said, adding that “Paul is a target because he is an American and anti-American sentiment is not uncommon among the other prisoners.” 

Paul Whelan’s parents have shared an audio recording of the call with the State Department and National Security Council so that they can address his safety with the Russian government, David Whelan said. 

The State Department and National Security Council did not immediately respond to a request for comment. 

Paul Whelan was arrested on espionage charges in 2018 while attending a friend’s wedding in Russia. He and his family have vehemently denied the espionage charges and the U.S. considers him to be wrongfully detained, a rare designation that puts the full force of the government behind securing his release. He was sentenced in 2020 to 16 years in prison and has been serving that sentence in a labor camp in Mordovia.

He has remained imprisoned while the U.S. has secured the release of Marine veteran Trevor Reed and WNBA star Brittney Griner, who were both wrongfully detained in Russia after his arrest. Both Reed and Griner were released in prisoner swaps between Washington and Moscow.

The U.S. is now also seeking the release of Wall Street Journal reporter Evan Gershkovich, who has been detained in Russia for 10 months on unsubstantiated espionage charges. On Tuesday, a Russian court extended his detention through the end of January as he awaits trial.

Whelan and his family have voiced concern that he could be left behind again as the U.S. seeks the release of Gershkovich. 

His sister, Elizabeth Whelan, visited Washington in September to pressure officials to do more to bring her brother home. 

“I don’t know what the Russians are asking for at this particular point, but whatever it is, it had better be possible,” she told CBS News at the time.